Vibratory roller

ABSTRACT

A VIBRATORY ROLLER HAVING A FRAME JOURNALING AN EARTH COMPACTING DRUM ADAPTED TO BE ROLLED OVER THE GROUND SURFACE, A POWER DRIVEN VIBRATING MECHANISM JOURNALED AXIALLY WITHIN THE DRUM, SAID MECHANISM INCLUDING MEANS FORMING DIAMETRICALLY OPPOSING FIRST AND SECOND LIQUID CHAMBERS WHICH COUNTERBALANCE EACH OTHER WHEN THE FIRST CHAMBER IS FILLED WITH LIQUID AND THE SECOND CHAMBER IS EMPTY, PASSAGE MEANS PROVIDING OPEN COMMUNICATION BETWEEN THE CHAMBERS, AND MEANS FOR ADMITTING GAS UNDER PRESSURE TO EITHER CHAMBER TO FORCE A DESIRED AMOUNT OF LIQUID FROM ONE CHAMBER TO THE OTHER TO SELECTIVELY DESTROY SAID COUNTERBALANCE AND CAUSE THE MECHANISM TO VIBRATE THE DRUM AT ANY DESIRED AMPLITUDE OR TO RESTORE SAID COUNTERBALANCE AND TERMINATE DRUM VIBATION.

Nov. 2, 1971 M. H. BOONE ETAL v 3,616,730

VIBRATQRY ROLLER Filed June 29. 1970 2 Sheets-Shee 1 INVIiN'IORS BRIAN J. BUSH MELVIN H. seem:

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Nov. 2, 1971 BQQNE ETAL 3,616,730

VIBRATORY ROLLER Filed June 29, 1970 2 Sheets$heet 2 INVI'IN'IURS BRIAN J. BUSH MELVIN H. BOONE 4 rromvsvs United States Patent Ofice 3,616,730 Patented Nov. 2, 1971 3,616,730 VIBRATORY ROLLER Melvin H. Boone, Fridley, and Brian J. Bush, Spring Lake Park, Minn., assignors to American Hoist & Derrick Company, Minneapolis, Minn.

Filed June 29, 1970, Ser. No. 50,519 Int. Cl. E01c 19/28 U.S. Cl. 94S0 V 7 Claims ABSTRACT OF THE DISCLOSURE A vibratory roller having a frame journaling an earth compacting drum adapted to be rolled over the ground surface, a power driven vibrating mechanism journaled axially within the drum, said mechanism including means forming diametrically opposing first and second liquid chambers which counterbalance each other when the first chamber is filled with liquid and the second chamber is empty, passage means providing open communication between the chambers, and means for admitting gas under pressure to either chamber to force a desired amount of liquid from one chamber to the other to selectively destroy said counterbalance and cause the mechanism to vibrate the drum at any desired amplitude or to restore said counterbalance and terminate drum vibration.

BACKGROUND OF THE INVENTION This invention relates generally to vibratory rollers used for the compaction of soil, asphalt or other ground surface materials. Generally, in such rollers the vibratory movement is created by one or more eccentric weights mounted on a power driven shaft extending axially through the roller drum. In such a construction varying dynamic forces are obtained by varying the speed of rotation of the shaft and the weights carried thereby. The forces are varied to change the amplitude of movement, or vertical distance of drum movement relative to the ground surface, strictly by varying the speed of rotation. Accordingly, amplitude is tied directly to rotational speed and it is not possible to have high amplitude with low rotational speed or vice versa.

It is desirable that the operator be able to control the amplitude independently of speed. This is due to the fact that optimum compaction results are achieved where the soil is compacted by vibrations at or near its resonant frequency. When a vibratory compactor is operated through a range of frequencies (vibrations per minute) with a constant dynamic force, there will be one frequency at which the soil will be compacted more effectively than at any other frequency. However, with a constant dynamic force, such as provided by fixed weights, the amplitude and frequency of vibration are not separable. High frequency (rotation) produces high amplitude (vertical movement) and low frequency produces low amplitude. Thus the desired degree of amplitude control at any given frequency is not possible in vibratory rollers using fixed weights.

In certain situations, such as compaction of a mat of asphalt road surface, it is desirable that the roller vibration have a high frequency but at a low amplitude and in other situations, such as compaction of relatively soft top soils, it may be desirable to have a low frequency of vibration at a relatively high amplitude.

One way of accomplishing this is by providing a means for selectively varying the weight of the eccentric means in the vibratory mechanism. This can be effected by providing liquid weight with suitable means for adding or removing liquid through lines connected to a remote reservoir. Such a structure is disclosed in copending application for United States Letters Patent Ser. No. 811,- 811, filed Apr. 1, 1969. While such a structure with a variable speed motor for rotating the vibrator operates satisfactorily, the present machine provides advantages thereover.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibratory roller wherein the vibrating mechanism includes liquid filled eccentric weights wherein the liquid weight may be selectively adjusted to vary the amplitude of movement of the roller without the necessity of providing an external liquid reservoir.

Another object of the invention is to provide a vibratory roller with liquid filled vibratory means wherein the force of vibration may be varied with displacement of only half of the normal amount of liquid.

With these and other objects in mind the invention broadly comprises a soil compacting drum mounted on a frame for rolling movement over the ground surface, a power driven vibratory mechanism journaled coaxially within the drum and including a pair of elongated tubes arranged parallel to and equidistant from the axis of rotation on diametrically opposite sides thereof, the tubes providing liquid chambers and one of the tubes when filled with a selected liquid being equal in weight to the other tube when empty so as to counterbalance each other during rotation of the vibratory mechanism and thus make the mechanism ineffective, means forming a fluid passageway between the tubes, and gas pressure means for forcing a predetermined amount of liquid from one tube to the other through the passageway to bring the tubes out of balance and cause the mechanism to vibrate the drum at the desired amplitude.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a longitudinal section taken along the axis of a roller drum embodying the vibratory mechanism with certain components of the operating system shown diagrammatically. The section is also taken longitudinally through the liquid carrying tubes of the mechanism with one of the tubes shown filled with liquid.

FIG. 2 is a vertical section taken diametrically through the lower portion of the drum taken on line 22 of FIG. 1, with the vibratory mechanism counterbalanced.

FIG. 3 is similar to FIG. 2 but with the vibratory mechanism partially out of balance to create limited amplitude of movement of the drum.

FIG. 4 is similar to FIGS. 2 and 3 with the vibratory mechanism almost completely out of balance to create near maximum amplitude of movement of the drum.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, reference characters will be used to denote like parts or structural features in the different views. The frame of a self-propelled or tractor drawn compactor has transversely spaced portions 10 which respectively journal shaft portions 11 and 12 in bearings 14. Shaft portions 11 and 12 are coaxially fixed one to each end of an elongated vibratory assembly denoted generally at 15 and to be shortly described in detail.

A drum denoted generally at 16 has spaced circular end walls 17 journaled centrally one on shaft portion 11 and the other on shaft portion 12 as by bearings 18. A cylindrical wall 19 is mounted peripherally on end walls 17 for rolling engagement over the ground surface G. It will accordingly be understood that drum 16- is rotatable on shaft portions 11 and 12 and that assembly 15 with its shaft portions 11 and 12 is independently rotatable in bearings 14 both on the same axis. Drum 16 is rotated by rolling engagement with the ground surface G. Assembly is selectively power driven by a fluid motor 20 having driving connection with the shaft portion 11.

Assembly 15 includes a pair of elongated tubes 21 and 22 arranged in parallelism to the axis of rotation on diametrically opposite sides thereof. The tubes are mounted on oblong end plates 24 and 25 respectively mounted on the inner ends of shaft portions 11 and 12. The end plates close the ends of tubes 21 and 22 forming enclosed liquid-tight chambers 26 and 2 7 therewithin. The internal diameters of tubes 21 and 22 are equal and the center axes of the tubes are equally spaced from the axis of rotation of assembly 15. The wall thickness and consequently the external diameter of tube 21 is slightly greater than that of tube 22 however. The difference is wall thickness is such that tube 21 with its chamber 26 empty will be equal in weight to tube 22 with its chamber 27 filled with a selected liquid L such as oil or water, as shown in FIG. 1. In this condition tubes 21 and 22 counterbalance each during rotation of assembly 15.

A transfer tube 28 extends diametrically between tubes 21 and 22 at the longitudinal centers thereof and is integrally connected thereto. This tube 28 extends through the adjacent walls of the liquid tubes and diametrically across the tube chambers 26 and 27 to points just short of the remote walls of the tubes. It accordingly provides an open passage between the chambers 26 and 27.

Shaft portion 12 has a passageway 30 extending axially therethrough with the inner end thereof being closed by a plug 31 having a recess 32 in its outer end. A passageway 34 extending through shaft portion 12 and end plate 25 connects the recess 32 with chamber 27. A second passageway 35, also extending through members 12 and 25, connects the passageway 30 with chamber 26. It will be noted in FIG. 1 that both passageways 34 and 35 connect with chambers 27 and 26 at the radially most inward part of the chamber.

An air pressure system shown diagrammatically is denoted generally by the number 40. It includes a pressure source 41 operated by pump 42. A stub pipe 44 has one end threaded into the outer end of shaft portion 12 and the other end connected to a rotary coupling 45. A second coupling 46 connects with coupling and the interior thereof has open communication with passageway 30. A third coupling 47 mounted on the second coupling 46 has its inner end connected to a tube 48 whichextends axially through couplings 46 and 45, stub pipe 44, passageway 30 and into recess 32. An annular rotating sealing member 49 supports the inner end of tube 48 and provide an airight seal around the tube between passageway 30 and recess 32.

A four-way control valve 50 is mounted on the operators platform of the tractive vehicle. Air line 51 connects pressure source 41 to the inlet side of the valve. An outlet port 52 is connected by line 54 to coupling 47. Port 56 is connected by line 58 to the coupling 46. The valve also has an exhaust port 57. The valve may be selectively operated by a suitable control to open line 51 to line 54 and simultaneously open line 58 to exhaust port 57 or in the alternative to open line 51 to line 58 and line 54 to exhaust port 57. It may also be turned to an intermediate condition in which all air passage therethrough is prohibited.

When it is desirable to use the drum 16 as a static roller, the vibratory assembly 15 is, of course, left in an idle condition with valve 50 closed. To initiate vibratory compaction the fluid motor 20 is activated to rotate the entire assembly 15 including shaft portions 11 and 12 and stub pipe 44. If all of the liquid L is. in chamber 27, as shown in FIGS. 1 and 2, the tubes 21 and 22 4 will counterbalance each other and vibrating assembly 15 will have no vibrating effect upon the drum 16.

To create vibrational forces of a low amplitude the operator adjusts the valve 50 to permit air under pressure to pass from reservoir 41 through lines 51 and 54, coupling 47, tube 48, recess 32 and passageway 34 into the chamber 27. At the same time chamber 26 is exposed to the atmosphere through passageways 35 and 30, coupling 46, line 58 and ports 56 and 57 of valve 50. Accordingly, pressure entering chamber 27 will force liquid through the transfer tube 28 into chamber 26 bringing the two tubes 21 and 22 out of balance and causing mechanism 15 and the drum 16 journaled thereon to 'vibrate during rotation. It will be understood that the difference in weight between the tubes 21 and 22 will be increased by twice the weight of the liquid transferred because tube 22 will decrease in weight the same amount as tube 21 increases. For every pound of liquid transferred the differential will be two pounds.

FIG. 3 depicts the condition when a relatively small amount of liquid L has been transferred to chamber 26. This will cause rather minimal amplitude of vibration of the drum upon the ground surface as denoted by the upper and lower limited lines indicated by spaced arrows A-A.

FIG. 4 depicts the condition when a relatively large amount of liquid L has been transferred to chamber 26. This will cause a relatively high amplitude of vibration of the drum upon the ground surface as denoted by the upper and lower limit lines indicated by spaced arrows BB.

Inasmuch as the liquid transfer'takes place during rotation of the assembly 15, the liquid in each tube 21 and 22 will, by centrifugal force, stay in the outer portions of the chambers 26 and 27 as shown. The inner portions of the tubes, near the axis of rotation, serve as air pockets. The extension of transfer tube 28 to closely spaced proximity to the outer walls of tubes 21 and 22 assures transmission of the liquid directly against the outer wall of the receiving tube. This prohibits any drainage of the liquid into air passageways 34 and 35.

The amplitude of vibration may accordingly be adjusted from zero with all of the liquid in chamber 27 to maximum with all or nearly all of the liquid in chamber 26.

When the operator wishes to decrease the amplitude or terminate the compacting operation valve 50 is adjusted to open line 51 to line 58. This admits air under pressure to chamber 26 forcing the liquid back through transfer tube 28 into chamber 27. As this occurs the air displaced by the liquid in chamber 27 returns through passageway 34, tube 48 and line 54 to valve exhaust port 57. When the desired balance of liquid in the chambers 26 and 27 is reached the valve 50 is turned to a neutral or closed position shutting off both passageways of air under pressure or exhaust air therethrough.

It will accordingly be understood that motor 20 controls the speed of rotation of the assembly 15 and consequently the frequency of vibration and the valve 50 controls the amplitude of vibration. Each is independent of and divorced from the other. There may be any selected amplitude of vibration from zero to maximum at any selected frequency from zero to maximum. The amplitude may be quickly varied as out of balance Weight is double the weight of the liquid transfer. Moreover, no external liquid reservoir is required. Oil or other liquids may be used as the liquid medium.

With the great variance in both frequency and amplitude the soil material worked upon may be vibrated at or near its resonant frequency.

Having now therefore fully illustrated and described the invention, what We claim to be new and desire to protect by 'United States Letters Patent is:

1. In a vibratory roller,

(a) a frame,

(b) a drum journaled on the frame for rolling engagement with the ground surface,

(c) a rotary assembly journaled axially within the drum,

(d) power means for rotating the rotary assembly relative to the drum,

(e) said rotary assembly having two liquid chambers disposed on diametrically opposite sides of the axis of rotation of the assembly,

(f) means providing an open liquid fiow passageway between the chambers,

(g) and gas pressure means for transferring liquid between said chambers through said passageway so as to selectively counterbalance the mechanism or convert it to various degrees of imbalance to cause vibratory movement of the assembly when rotated.

2. The subject matter of claim 1 wherein said rotary assembly comprises a pair of elongated parallel closed end tubes disposed on opposite sides of and Parallel to the axis of rotation of the assembly to form said chambers.

3. The subject matter of claim 2 wherein the axis of said tubes are equally spaced from said axis of rotation and one of said tubes when filled with a selected liquid being equal in weight to the other of said tubes when empty to counterbalance the assembly.

4. The subject matter of claim 1 wherein said pressure means comprises a source of gas under pressure, conduit means leading from said source to each of said chambers, and valve means in said conduit means for selectively admitting gas under pressure to either of said chambers.

5. The subject matter of claim 1 wherein said passageway is formed by a tube extending diametrically between said liquid chambers to points near the outer walls thereof.

6 6. The subject matter of claim 4 wherein said conduit means open into said chambers adjacent to the inner walls thereof relative to the axis of rotation.

7. In a vibratory roller,

(a) a frame,

(b) a drum journaled on the frame for rolling engagement with the ground surface,

(c) a rotary assembly journaled axially within the drum,

(d) power means for rotating the rotary assembly about its axis and relative to the drum,

(e) said rotary assembly including self-contained shiftable liquid weight for converting the assembly between counterbalance and out of balance conditions during rotation to convert rolling movement of the drum between static and vibratory rolling conditions, and

(f) gas pressure means independent of said power means for shifting said liquid weight within the rotary assembly.

References Cited UNITED STATES PATENTS 2,955,476 10/1960 Geil 74-87 2,963,914 12/1960 Dupouy 74-87 3,020,683 2/1962 Brandt 74-87 X 3,052,166 9/1962 Thrun 74-87 X 3,078,730 2/ 1963 Clements 74-87 3,217,551 11/1965 Bodine 74-87 JACOB L. NACKENOFF, Primary Examiner US. Cl. X.R. 74-87 

